1. Field of the Invention
The present invention relates to a control apparatus for air conditioners used for vehicles, and more particularly, to a control apparatus able to control the temperature and volume of air in the air conditioner to thereby compensate for solar radiation and give a comfortable feeling to a person in the vehicle.
2. Description of the Related Art
There are many known controlling apparatus which can correct and control the temperature and/or volume of air in an air conditioner of a vehicle according to the quantity of solar radiation coming into the room of the vehicle.
For example, Japanese Unexamined Patent Publication No. 56-86815 calculates a required air temperature with an equation involving a term of the quantity of solar radiation, and according to the calculated temperature, controls the volume of air from a blower of the air conditioner and the opening of an air mixing damper of the air conditioner, thereby changing the volume and temperature of air to be blown from the air conditioner according to the quantity of solar radiation.
Japanese Examined Patent Publication No. 58-20810 changes volumes of air to be fed to upper and middle layers in the vehicle room according to the quantity of solar radiation, thereby compensating for the solar radiation.
Japanese Examined Utility Model Publication No. 59-34497 and Japanese Examined Patent Publication No. 63-45965 blows cool air from a ventilation diffuser even during heating due to solar radiation.
Japanese Unexamined Patent Publication No. 56-86815, however, pays no attention to whether or not ventilation and/or heating operations are being carried out when controlling the temperature and volume of air according to the quantity of solar radiation. If the quantity of solar radiation increases during heating to thus change a required air temperature, the disclosure reduces the heating temperature and volume, thereby lowering the temperature around the feet of a person in the vehicle even during a period in which heating is required. In addition, no ventilation takes place to compensate for the solar radiation during the heating, so that the upper body of the person in the vehicle, which is particularly influenced by the solar radiation, may not be cooled.
Japanese Examined Patent Publication No. 58-20810, Japanese Examined Utility Model Publication No. 59-34497, and Japanese Examined Patent Publication No. 63-45965 change only the temperature and volume of ventilation air according to the quantity of solar radiation, and this may prevent the feet of the person in the vehicle from being cooled. These techniques, however, simply lower the air temperature and increase the air volume when solar radiation is felt, and thus in some cases, the air temperature may be excessively lowered and the person in the vehicle may feel too cold.
A diffuser of the vehicle air conditioner is usually positioned not far from the face of the person in the vehicle, and thus the person is sensitive to the temperature of air from the diffuser, and feels comfortable or uncomfortable accordingly. It is, therefore, very important to control the temperature of air to ensure the comfort of the person in the vehicle.